Vibration generator adjustable during operation

Abstract

A vibration generator comprises a first rotational shaft 21 and second rotational shaft 22, with fixed driving gears 31 and 33, movable driving gears 32 and 34, fixed eccentric weights 51A and 52A, and movable eccentric weights 51B and 52B, and on the outer periphery of the phase adjustment shaft 23 which is arranged in parallel therewith, spiral grooves 61 and 62 are provided at two locations in the rotative directions opposite to each other, and at the same time, on the inner periphery of a pair of phase adjustment gears 35 and 36, pins 63 and 64 are planted to be slidably fitted into the above-mentioned spiral grooves 61 and 62. Then, the phase adjustment shaft 23 is forced by a cylinder 50 in the axial direction. The vibromotive force can be varied arbitrarily and infinitely, even during operation; yet the structure is simple and rational, and is fabricated easily.

What is claimed is: 
     
       1. A vibration generator comprising: a first rotational shaft rotatively supported by a casing member with a first fixed driving gear and a first fixed eccentric weight fitted thereto from the outside and at the same time, a first movable driving gear and a first movable eccentric weight coupled to said gear fitted thereto from the outside to be relatively rotative;   a second rotational shaft rotatively supported by said casing member in parallel with said first rotational shaft and with a second fixed driving gear to engage said first fixed driving gear and a second fixed eccentric weight fitted thereto from the outside and at the same time, a second movable driving gear to engage said first movable driving gear and a second movable eccentric weight coupled to said gear being fitted from the outside to be relatively rotative;   a phase adjustment shaft arranged in parallel with said first and second rotational shafts and rotatively;   a pair of phase adjustment gears, at least one of which is fitted to said phase adjustment shaft from the outside to be relatively rotative in such a state that is traveling in the axial direction is restricted, and one of them engaging either one of said first and second fixed driving gears and the other engaging either one of said first and second movable driving gears; and   phase changing means for relatively rotating one of said pair of phase adjustment gears with respect to the other.   
     
     
       2. The vibration generator according to claim 1, wherein said phase changing means comprises: a motion converting means for converting the linear motion of the phase adjustment shaft in the axial direction to the relative rotation of said phase adjustment gear; and a driving means for forcing said phase adjustment shaft in the axial direction.   
     
     
       3. The vibration generator according to claim 1, wherein said phase changing means comprises: a spiral groove or convexity provided in two locations on the outer periphery of the phase adjustment shaft in the rotative directions opposite to each other;   a convex portion or concave portion provided on the inner periphery of the pair of phase adjustment gears to be slidably fitted into said spiral groove or convexity; and   a driving means for forcing said phase adjustment shaft in the axial direction.   
     
     
       4. The vibration generator according to claim 1, wherein the phase changing means comprises: a pin provided projectingly through the phase adjustment shaft in a radial direction;   an elongated boss portion provided connectively at least to one of said pair of phase adjustment gears with a spirally elongated hole formed thereon to enable said pin to be fittingly inserted; and   a driving means for forcing said adjustment shaft in the axial direction.   
     
     
       5. The vibration generator according to claim 4, wherein small-diameter elongated boss portions and large diameter elongated portions, each one of which is inserted into the other, are provided connectively to the pair of phase adjustment gears respectively, and the spirally elongated holes having opposite phases are formed on these elongated boss portions to enable said pin to be fittingly inserted thereinto. 
     
     
       6. A vibration generator comprising: a first rotational shaft rotatively supported by a casing member with a first fixed driving gear and a first fixed eccentric weight fitted thereto from the outside and at the same time, a first movable driving gear and a first movable eccentric weight coupled to said gear fitted thereto from the outside to be relatively rotative;   a second rotational shaft rotatively supported by said casing member in parallel with said first rotational shaft and with a second fixed driving gear to engage said first fixed driving gear and a second fixed eccentric weight fitted thereto from the outside and at the same time, a second movable driving gear to engage said first movable driving gear and a second movable eccentric weight coupled to said gear being fitted from the outside to be relatively rotative;   a phase adjustment shaft comprising a first adjustment shaft and a second adjustment shaft, being arranged in parallel with said first and second rotational shafts and rotatively, and further, the first adjustment shaft being arranged to be relatively traveled in the axial direction and relatively rotative with respect to the second adjustment shaft through a first motion converting means to convert linear motion to rotational motion;   a pair of phase adjustment gears, one of which is fitted from the outside to either one of the first adjustment shaft and second adjustment shaft and the other of which is fitted from the outside to the other one of the first adjustment shaft and second adjustment shaft respectively, and one of them engaging either one of said first and second fixed driving gears and the other engaging either one of said movable driving gears; and   a driving means for forcing at least one of said first adjustment shaft and second adjustment shaft in the axial direction.   
     
     
       7. A vibration generator comprising: a first rotational shaft rotatively supported by a casing member with a first fixed driving gear and a first fixed eccentric weight fitted thereto from the outside and at the same time, a first movable driving gear and a first movable eccentric weight coupled to said gear fitted thereto from the outside to be relatively rotative;   a second rotational shaft rotatively supported by said casing member in parallel with said first rotational shaft and with a second fixed driving gear to engage said first fixed driving gear and a second fixed eccentric weight fitted thereto from the outside and at the same time, a second movable driving gear to engage said first movable driving gear and a second movable eccentric weight coupled to said gear being fitted from the outside to be relatively rotative;   a phase adjustment shaft comprising a first adjustment shaft and a second adjustment shaft and being arranged in parallel with said first and second rotational shafts and rotatively, and further, the first adjustment shaft being arranged to be relatively traveled in the axial direction with respect to the second adjustment shaft;   a pair of phase adjustment gears, one of which is fitted from the outside to either one of the first adjustment shaft and second adjustment shaft to be relatively rotative through a second motion converting means to convert linear motion to rotational motion, and the other one of which is fitted from the outside to the other one of the first adjustment shaft and second adjustment shaft, and one of them engaging either one of said first and second fixed driving gears and the other engaging either one of said first and second movable driving gears; and   a driving means for forcing at least one of said first adjustment shaft and second adjustment shaft in the axial direction.   
     
     
       8. A vibration generator comprising: a first rotational shaft rotatively supported by a casing member with a first fixed driving gear and a first fixed eccentric weight fitted thereto from the outside and at the same time, a first movable driving gear and a first movable eccentric weight coupled to said gear fitted thereto from the outside to be relatively rotative;   a second rotational shaft rotatively supported by said casing member in parallel with said first rotational shaft and with a second fixed driving gear to engage said first fixed driving gear and a second fixed eccentric weight fitted thereto from the outside and at the same time, a second movable driving gear to engage said first movable driving gear and a second movable eccentric weight coupled to said gear being fitted from the outside to be relatively rotative;   a phase adjustment shaft comprising a first adjustment shaft and a second adjustment shaft and being arranged in parallel with said first and second rotational shafts and rotatively, and further, the first adjustment shaft being arranged to be relatively traveled in the axial direction and relatively rotative with respect to the second adjustment shaft through a first motion converting means to convert linear motion to rotational motion;   a pair of phase adjustment gears, one of which is fitted from the outside to either one of the first adjustment shaft and second adjustment shaft through a second motion converting means to convert linear motion to rotational motion, and the other one of which is fitted from the outside to the other one of the first adjustment shaft and second adjustment shaft, and one of them engaging either one of said first and second fixed driving gears and the other engaging either one of said first and second movable driving gears; and   a driving means for forcing at least one of said first adjustment shaft and second adjustment shaft in the axial direction.   
     
     
       9. The vibration generator according to claim 6 or claim 8, wherein the first motion converting means comprises a first spirally irregular portion cut in the inner periphery of the first adjustment shaft and a second spirally irregular portion cut on the outer periphery of the second adjustment shaft to be fittingly inserted into said first spirally irregular portion.   
     
     
       10. The vibration generator according to claim 7 or claim 8, wherein a second motion converting means comprises a third spirally irregular portion cut on the inner periphery of one of the phase adjustment gears and a fourth spirally irregular portion cut on the outer periphery of the phase adjustment shaft to which said phase adjustment gear is fitted from the outside to be fittingly inserted into said third spirally irregular portion.   
     
     
       11. The vibration generator according to claim 8, wherein the directions of the rotational conversion by the first motion converting means and second motion converting means are the same. 
     
     
       12. A vibration generator comprising: a first rotational shaft rotatively supported by a casing member with a first fixed driving gear and a first fixed eccentric weight fitted thereto from the outside and at the same time, a first movable driving gear and a first movable eccentric weight coupled to said gear fitted thereto from the outside to be relatively rotative;   a second rotational shaft rotatively supported by said said member in parallel with said first rotational shaft and with a second fixed driving gear to engage said first fixed driving gear and a second fixed eccentric weight fitted thereto from the outside and at the same time, a second movable driving gear to engage said first movable driving gear and a second movable eccentric weight coupled to said gear being fitted from the outside to be relatively rotative;   a phase adjustment shaft arranged in parallel with said first and second rotational shafts and rotatively; and a pair of phase adjustment gears, at least one of which is fitted from the outside to said phase adjustment shaft to be relatively rotative in a state that its traveling in the axial direction is restricted, and one of them engaging either one of said first and second fixed driving gears and the other engaging either one of said first and second movable driving gears, wherein   a fluid actuation chamber is formed between the outer periphery of said adjustment shaft and one of said phase adjustment gears, and the structure is arranged to enable said phase adjustment gear to relatively rotate with respect to said phase adjustment shaft.   
     
     
       13. The vibration generator according to claim 12, wherein the liquid actuation chamber is partitioned by a fixed partition wall portion fixed to the phase adjustment shaft and a movable partition wall portion fixed to the phase adjustment gear.